ChIP was performed as previously described (Lee et al., 2006) by using Zfp281 antibody (Abcam #ab101318). 25 μl of 70 ng/μl input and 5 ng/μl Zfp281-ChIPed DNA to prepare input and Zfp281 ChIP-seq libraries. Massively parallel sequencing was performed with the Illumina HiSeq 2500 Sequencing System according to the manufacturer’s protocol.